Creatures Playground kodai:

Caveman Norn:

Go fishing until you get a bone. Complete the ghost ride.
Go in the red jet-ski in the snow/space area, In the cave,
crack all the rocks. In the mine, walk up to the bones.
You should now have a caveman Norn. If you open the gate
with the dragon when the caveman is near, the dragon should
be scared off and you will get a part of the puzzle.

Alien Norn:

Bo to the space ship (near the snow area). In the background, you should find a gold door (similar to the one with the rocket).
Click it and an alien will appear. Note: You cannot control the creatures until it is full sized.

Town Square bonuses:

The following things can be found in the village area.
You must have merged Creatures Adventures and Playground to
do this. Note: You will have a camera for your ride as soon
as you merge.

Rainbow (make your own ride):

Click on the plant that is by the lift.
Skull Fort (make your own ride): Click on the mother duck.
Melon Candy Floss: Click on the till in the clothes shop.

Secret Mad Labs:

Take your Norn to the mines. Directly in front of the coal
conveyor belt should be a yellowish-golden panel on the ground. Click the panel then move your Norn onto it. He or she should drop into the Mad Labs. Once there, you can change your Norn's skin, color, hair and even change them into a toy.